Suggest Treatment For Redness And Itching On Whole Body

I bought TrimSpa at the drugstore about two weeks ago, and took it for approx. 4-5 days. I suddenly started experiencing fever, vomiting and diarrhea. Those symptoms cleared up, but then the constant itching started and has been going on for about a week now. It's all over my body except for my face and scalp. It has caused raw painful, red chafing as well in the groin area (folds of skin on thighs) from scratching so much. There is no visible rash in just one area, my whole body is red and irritated from scratching. The only visible evidence is on the sides of my fingers.. tiny little itchy dry bumps. I've been taking Benadryl for 3 days now which temporarily eases the itch. Also, it feels as though it's coming from inside my body in several different places at one time. I just wonder what I should do and how long this may last, and ultimately, if this reaction is serious enough to see a doctor. Thank you.